A parade of bright-eyed teens marched to the third floor of the State House last week chanting, “Youth united will never be defeated!” — and then they slammed into the hard reality of how business is done on Beacon Hill.

One girl in a striped shirt and hoop earrings shouted, “Youth jobs!” and pumped her fist in the fight for more state funding to put teens to work.

“You’re being heard. You’re making a difference,” state Rep. Thomas P. Conroy (D-Wayland) told the makeshift pep rally outside the House chambers.

But only a handful of lawmakers milled around the House floor. Unbeknownst to the teens, dozens of reps were crammed into Room 348, a small office tucked down the House’s “Members Only” hallway. The lawmakers were secretly hashing out deals on how budget money should be doled out.

The private room, anchored by a simple oval conference table and about a dozen high-backed chairs, is where many House spending pitches for the state’s $36.3 billion budget live or die — all out of public view.

It’s a symbol of what the House budget process has become — where efficiency has come at the price of transparency.

The deals cut in Room 348 are so secretive the public is not allowed to enter or photograph the hallway leading to the room — even when it’s completely empty. A Herald photographer who snapped a photo of the vacant room when the House was not in session was asked to leave after State House staffers said the area was off-limits.

Because lawmakers are exempt from the state’s Open Meeting Law, only House members know what is said in Room 348. Several past and current lawmakers — both Democrats and Republicans — described a hectic scene in the room as rank-and-file members pitch pet projects to the budget’s main gatekeepers, including the House Ways and Means Committee chairman, a seat now held by state Rep. Brian Dempsey (D-Haverhill).

Members repeatedly retreated to Room 348 during last week’s budget debate, where Dempsey, his staff and other leaders listened to scores of lawmakers plead for local projects to be included in so-called consolidated amendments — large budget add-ons grouped by spending category and adopted by the House in recent years to avoid House floor debate.

“It’s a feeding frenzy,” said state Rep. Christopher Fallon (D-Malden). “It’s a little more refined, a little less barbaric. Dempsey’s a patient guy, but I think the result is pretty much the same. Debate is certainly restricted, no doubt about it.”

After the scrum in Room 348, Dempsey, his staff and other House leaders retreat to a back office and decide which proposals will survive. Members are given as little as 30 minutes to review the final consolidated amendment before the vote.

Dempsey brushed off the lack of public access to the secret sessions in Room 348, saying, “The reps are the public. The reps are representing their constituents, and they’re fighting for their constituents.”

House Speaker Robert A. DeLeo defended the process in a statement to the Herald.

“Any member can choose to debate any amendment individually,” DeLeo said. “I’m proud of the budget we passed.”

Neither Conroy nor the other 42 lawmakers who supported more funding for teen jobs requested a public debate or vote on the measure. Conroy wouldn’t say what was said in Room 348 about the teens’ appeal for more money — or what back room deal may have killed it. He did raise the possibility teen jobs funding could be increased from $8 million to $12 million in a supplemental budget next year.

“I’m not going to say promises were made. I’m not going to put anyone in a difficult position, but discussions were had on that topic,” said Conroy, chairman of the Joint Committee on Labor and Workforce Development and a state treasurer candidate. “It’s not a matter of transparency. These discussions are ongoing. They don’t need to happen on the floor of the House. If we did that, we might be in session talking about the budget for six months.”

Dylan Lazerow of the Youth Jobs Coalition wasn’t impressed.

“It seems almost comical to call some of this democratic,” he said. “It’s certainly frustrating. The teenagers that you see in the State House now understand a little bit more about the budget process. Maybe one day they’ll become elected and make it a more transparent process.”